When I bought my 5.4 SCrew in 2006, I had a muffler shop install a SI/DO Magnaflow muffler. Never even thought about running true dual. Recently, I've been thinking about taking it back and having that shop install two SI/SO Magnaflow mufflers. They guy at the shop told me that it really isn't going to sound or perform any different than my current setup. So, what are your thoughts? Is this guy right? I like the way my current setup sounds, but I would like it to sound a little deeper and ballsyer.

 

It will sound slightly different ( if you choose to go with the same muffler you have now ). It will be louder under WOT, and have a more, dual exhaust rumble, under cruising. What size is the muffler you currently have,as in length? 14"? 18?". Are you looking to go a bit louder? Are there other brands you are more interested in trying?

If you're ready for some more rumble, the 14" round body Magnapacks will make you quite happy.

 

I can confirm that fo sho!

Oh and thanks for those dimensions Darren.

 

I don't what size I have one there now, but I will measure it tonight and post it. I'd like to stick with Magnaflow. I would like it louder, but I don't want to annoy the hell out of the neighbors either. I guess I just don't know enough about it to tell the guy at the muffler shop what I want. I just asked him about going to true dual. I asked him about an x-pipe and he said in his opinion, I did not need it. However, it seems that just about everyone here has them on their truck. Like I said, I just don't know enough about it to talk shop with this guy. He did tell me that he's not trying to talk himself out of a sell, he just wouldn't spend the money for what little difference I would notice... performance wise and sound wise.

 

You dont NEED a crossover, but if your running true duals with no crossover, your low end tq will be in the pooper. Personally, I would save my dough and install high flow converters. That will open the system up by about 40%.

 

^ agreed. I would also spend my money on the cats first.

 

yeah if you want a bit louder just add high flow cats and keep your si/do muffler.

 

So I called the muffler shop about getting the high flow cats installed and they quoted me $724.30. That seems a little high to me considering I only paid $275 for them to install the muffler. So does that sound about right, or about crazy? Maybe I didn't communicate what it was that I wanted. Is there a certain model I need for my truck?

 

Find a shop that doesn't rip their customers off, and buy the cats from performancepeddler.com, coupon code "bestoffer4em".

 

Wow, $100.00 for two of them! Thanks for the coupon code! I'm guessing I need Magnaflow part #94006. One for the front and one for the rear?

 

thats were i bought my x pipe, muffler, high flows, and headers. Great place. Got it all for 806.76 Now i need to find a good place to install it. lol I went to sooner muffler down here and they wanted 350.00 to just install the cats, muffler and x pipe. Which i thought was a little steep. Sorry to thread jack back to your topic lol

 

Ok, so I think I am definitely going to order two of these 94006 High Flow cats. I found a shop that will install the "bolt on's" for $125 and "weld on's" for $175. My question is, after looking around here on the forums, I see all these mentions of front cats, rear cats, pre-cats so it's a bit confusing for me. Considering all I have done thus far is have the stock muffler replaced with a Magnaflow Si/Do, which of the three cats is this 94006 going to replace? Just want to make sure I am getting the right thing. The consensus seems to be that by doing this I will open the system up by 40% and make it louder. Is this going to cause this O2 CEL that others have posted about?

 

Go for 94106's.

 

I'll try to answer this the best way I can but your truck only has 2 cats total (1 per side; just like mine). Some have 2 per side. Some call the first cat a pre-cat and some call it the front cat. The rear cat is the 2nd cat for the 2 per side guys. Your exhaust guy will mount the new hi flows in the same vicinity as your factory cats and mount the O2 sensor in after the hi flows. Mine have been done like this for almost 2 months now and haven't had a sensor light yet. Not to say that you won't but there are ways to fix that also. A programmer can delete it or you can do the Gotts O2 mod.

Gotts O2 mod

Take a look at my signature vids and they may help you determine how you like Hi flows.

^x2. Best exhaust investment I've made was putting on my 94106s.

 

That is very high for just catalytic converter work.$200 max is what converter labor should be. Could knock $50 off that for letting them keep your OEM cats.

$100 is actually a real good deal considering the fantastic quality of the units, OEM cat replacements are $350. 94306, 94006, or 94106 will work. All are listed from calmest to loudest.